Abstract. Model simulations and remote sensing observations show that ocean dynamics at fine scales (1–100 km in space, day–weeks in time) strongly influence the distribution of phytoplankton. However, only few in situ samplings have been performed and most of them in boundary currents which may not be representative of less energetic regions. The PROTEVSMED-SWOT cruise took place in the moderately energetic waters of the western Mediterranean Sea, in the southern region of the Balearic Islands. Taking advantage of near-real time satellite information, a sampling strategy was defined in order to cross a frontal zone separating different water masses. Multi-parametric in situ sensors mounted on the vessel, on a towed fish and on an ocean glider were used to sample at high spatial resolution both physical and biogeochemical variables. A particular attention was put in adapting the sampling route, in order to also estimate the vertical velocities in the frontal area. Such a strategy was successful in sampling quasi-synoptically an oceanic area characterized by the presence of a narrow front with an associated vertical circulation. A multiparametric statistical analysis of the collected data identifies two water masses characterized by different abundances of several phytoplankton cytometric functional groups, as well as different contents in chlorophyll a and O₂. Our study shows that the Lagrangian fronts induced by the fine-scale circulation, even if much weaker than the fronts occurring in boundary current systems, maintain a strong structuring effect on phytoplankton community by segregating different taxa at the surface.

中文翻译：

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中度能量细尺度动力学对地中海西部浮游植物群落结构的影响

摘要。模型模拟和遥感观测表明，小尺度的海洋动力学（空间上为1–100 km，一天至几周的时间）强烈影响浮游植物的分布。但是，仅进行了很少的原位采样，而大多数采样是在边界电流中进行的，这可能并不代表能量较低的区域。PROTEVSMED-SWOT巡游是在地中海西部中等强度的水域，巴利阿里群岛的南部地区进行的。利用近实时卫星信息，定义了一种采样策略，以便越过分隔不同水团的前沿区域。安装在船上，拖曳的鱼和滑翔机上的多参数原位传感器用于以高空间分辨率对物理和生物地球化学变量进行采样。特别注意调整采样路径，以估计额叶区域的垂直速度。这样的策略成功地准同等采样了一个海洋区域，该区域的特征是存在一个狭窄的锋面以及相关的垂直环流。对收集到的数据进行多参数统计分析，可以确定两个水团，其特征是几个浮游植物细胞功能组的丰度不同，并且叶绿素含量不同a和O ₂。我们的研究表明，由精细尺度环流引起的拉格朗日锋，即使比边界流系统中的锋线弱得多，也可以通过在表面分离不同的分类单元来维持对浮游植物群落的强大构造作用。